Low film basis weights may increase a film's thermal sensitivity to hot melt systems. As a result, the risk of hot melt adhesives burning through the film increases. Glue burn through (GBT) occurs when the hot glue partially or completely melts the polymeric film in an area so that the thickness of the polymer is reduced or no longer exists. Glue burn through can occur by two different mechanisms: instantaneous melting or mechanical pressure. Instantaneous melting occurs when the film melts instantaneously when the hot adhesive contacts the web, usually resulting in contamination severe enough to tear the film web. When glue burn through occurs from the mechanical pressure mechanism, the glue and film are in contact and the area goes under a mechanical nip. The mechanical nip applies pressure to the area where the soft film pores collapse or forces the glue through the film. Glue burn through can potentially impact the product by eliminating or weakening the film structure or altering the opaqueness of the film. Thus, the film is diminished in performance (may cause leakage from pinholes or thermal melting), integrity (could tear easily), and appearance (looks plastic/cheap or consumer perceives it as product failure).
Higher basis weight films typically do not exhibit glue burn through. However, higher basis weight films are more expensive than lower basis weight films. Conversely, lower basis weight films are less expensive than higher basis weight films, but many lower basis weight films exhibit glue burn through. Thus, a need exists for a lower basis weight film that exhibit lower glue burn through.